Kid Flash
by LovelyKnight
Summary: Robin isn't really the youngest member of Young Justice, Kid Flash is. The only people who know other than Wally are his family and Batman. When he attempted his uncle's experiment, something went... wrong. Now a 10 year old Wally has the body of a 15 year old. Gen fic. Title liable to change.
1. The Lightning Flashed

_"Our sources report that Central's own, the Flash, has torn a page from Batman's book and taken on a sidekick of his own. The young speedster is allegedly going by the moniker "Kid Flash". Based on who gifted it to him, however, this name is either very patronizing or very ambitious._

_"The photos gathered identify the new hero as in their late teens or young adulthood. While the people are relieved that our beloved hero hasn't taken in an elementary schooler, it brings to mind some unexpected questions; How old is the Flash that his sidekick is able to be called a "kid" in comparison? And, to bring up the obvious, where did Kid Flash come from? Is he perhaps the Flash's son? Is that his natural hair color? More as the situation develops on channel 5, CCNN."_

A young man grimaced, shifting his gaze to his uncle as the station transitioned to its usual reel. The other obviously seemed equally distressed by the news broadcast, as he had taken to biting his nails.

"I'm sorry, uncle Barry," Wally whispered, ducking his head in shame. "I honestly didn't mean for it to turn out like this..."

Barry sighed, still gazing at the television. "I know, Wally. I know."

* * *

Wally had been waiting for weeks so that an opportunity such as this one might occur. In secret, the ten year old had gathered chemicals and spare electric parts from the scrap yard, all the while reading heavy chemistry tomes or scribbling away into a notebook. He had already been studious, so no one had thought of it as unusual.

He waited with bated breath as his aunt and uncle backed out of the garage, just barely keeping himself from going out early, potentially ruining his entire quest. At the last minute, Wally ducked under the closing door and into the garage. Thankfully, his uncle Barry was distracted by something his Aunt Iris asked him.

After allowing himself to gloat for a moment, Wally rushed to set up his experiment. He carefully rebuilt his lightning generator, taking extra care to put every piece in its proper place.

The generator was something that Wally was especially proud of, since he had built it from scratch. He had siphoned the design from a few 'do it yourself' videos on the internet, modifying it to fit his experiment. For this to work, he'd need a very specific amount of electricity to flow through his body. If it weren't for that, Wally probably would have just stuck a knife in an electric socket.

Wally listened carefully as the car left the driveway, waiting a full minute afterwards to make sure that it was actually gone. Finally, Wally felt assured that his relatives had left. "Alright, Wall-man. You've only got one shot at this..." The youth muttered, glancing at his watch nervously.

Wally took a deep, calming breath and in one swift motion, the 10 year old dumped the various chemicals over his head and switched his device to its highest setting.

He only had a moment to brace himself as red-hot electricity coursed through his body, pseudo-lighting scorching skin already burned from the chemicals. His mouth was torn open by a spine-chilling scream without his permission. A second too late, he reached over and switched off the device.

The world went dark.

* * *

"How is he?"

Dr. Leslie Thompkins had often treated superheros throughout her career, although it wasn't often that she treated supers. She supposed that is was a testament to her abilities that Bruce would refer her to one.

"His body is completely healed, not a scratch on him. However, there do seem to be a few… complications with his normal body functions."

The Flash's face darkened, and he slammed a fist on the wall beside him. Flakes of plaster rained down upon the two of them. "Don't give me any of this censoring bullshit!" He raged, "I don't care how technical it is or how gruesome! I need to know how he is!"

Dr. Thompkins gave the other an unimpressed once-over. She was long used to patients taking out their anger on her and she hadn't expected any different from him.

"His cells are going through their normal processes at an accelerated rate. They are reproducing, dying, everything at several times their average speed. It's different from how your speed works on a fundamental level. When you access your speed your cells function normally, despite the vibrations. Wally, however, has cells that are vibrating on the level of his cell's organelles. This is causing the cell to speed up as well. He obviously does not have control enough over his powers to slow down."

"But what does that mean for Wally?" The Flash cut in, vibrating anxiously in place. If the situation were different, Leslie supposed that it would have been funny.

She sighed and lowered her clipboard, meeting the blue eyes of the Flash. "His body is aging rapidly. If we don't stop it soon, he may outlive the both of us."

The Flash's breath hitched and he stared at her in disbelief. "That… doesn't happen to me." He stated blankly.

Dr. Thompson ignored his statement for the most part and gestured for him to go with her. "It shouldn't happen to him either. This could be happening for any number of reasons… However, I can't imagine what since his body has healed any evidence of the supposed 'experiment' that you told me about."

The Flash followed, tapping his fingers rapidly on his thigh in order to restrain himself from speeding off toward Wally's room. "Is there anything I can do?" The sentence was mumbled, spoken almost too fast for the doctor to hear.

She nodded, "If you are able to vibrate at his exact frequency you may be able to trick Wally's cells into thinking that you are a part of him. Once you've done this, you'll need to gradually slow down your vibrations until they are that of a normal human's and Wally's cells will, hypothetically, do the doing this, you will remind Wally's cells of the proper frequency and he will be stabilized. So long as you train him immediately, this shouldn't happen again." She gave the Flash a sidelong look and added, "This is all a theory, of course."

The Flash caught a hold of Dr. Thompson's hand, pulling her to a halt. His eyes shone with determination. "So long as it had even the slightest chance to save him, I'll do it. Bruce recommended you and I trust him, so I trust you. When can we try?"

She met his eyes and and assessed him. Obviously, she found what she was looking for as she whirled around and continued onto Wally's room. "I suggest you brace yourself." She advised. "He isn't exactly himself."

"I'm prepared to face anything." He told her bravely.

The doctor led him to a room far off from the rest of her clinic's occupants, the only sign that someone was inside was the scribbled 'Wallace West' on the nameplate. The Flash sped off ahead of her into the room.

When she finally caught up with him, she was met by a blank-faced Flash.

"You wouldn't believe how much morphine it's taking to keep him out." She commented offhandedly in a weak attempt to lighten up the situation. "We've also set up a very large IV bag in order to keep his body sustained on nutrients. We've been switching it out every few minutes."

The Flash was horrified. "I don't even recognise him!" He wailed, bringing a hand up to run his fingers through his hair, only to start when he was met with the thin material of his suit.

The doctor watched as Flash hesitantly went over to his nephew's bedside and grabbed the child's hand. He only gripped it harder as he realized that it was vibrating.

"How old is he physically?" He whispered.

"He has aged approximately 5 years." She answered in a monotone.

"Oh, God." Flash breathed, "5 years… gone. Oh my god, Wally…. Wally, Wally, Wally…" Flash chanted his name like a prayer, his mask growing suspiciously wet. His frantic whispers were cut short by a firm hand on his shoulder.

"You can mourn later." Leslie told him sharply. "Right now he's still alive but he's only going to get older the longer we wait."

Flash's face grew hard and he finally pried his hands away from Wally's and moved them so that they were hovering over the redhead's chest. "I'm ready." He declared, voice determined.

"Just make sure you don't go too fast. It's a matter of a lack of control rather than his speed. If you go too fast he'll age even faster."

Flash twitched fractionally in what could be perceived as a nod and he lowered his hands to Wally's chest.

They stood in silence as the speedster searched carefully for the correct frequency. Finally, after several agonizing minutes, Flash cried, "I've got it!"

"Good. Now slow down _gradually_. His cells could be damaged or he may go into shock if you go to fast."

"Got it." He replied tersely, focused on his task.

Slowly, perhaps more slowly than strictly necessary, the Flash returned to normal speed. At last, Wally was back to normal and the Flash collapsed over his nephew from exhaustion.

"You wouldn't think that slowing down would take more energy than speeding up." Flash quipped, sitting up weakly. The visible parts of his skin gleamed with a thin layer of sweat.

Dr. Thompkins nodded distractedly and checked Wally's vitals. She breathed a sigh of relief when she found them to be normal. "It worked." She proclaimed, switching off the morphine drip.

"Thank god." Was Flash's resounding response.

Immediately after the morphine was switched off, Wally showed the signs of waking up. The doctor stared in shock. "How fast is his metabolism?" She wondered aloud.

The Flash chuckled, pulling himself properly into the bedside seat. "That probably has something to do with his going through puberty, as well." He remarked, pulling a protein bar from a strange compartment in his suit.

Wally shifted noticeably, drawing their attention. The redhead swallowed, his adam's apple bobbing- and, oh, if that wasn't another blow to Flash's guilt! Hours earlier the child had been, well, a child. He had whined about wanting his growth spurt and now he was easily his height.

Red eyelashes parted to reveal groggy green eyes staring blankly up at the ceiling. The Flash almost fell over with relief and he pulled his nephew into a tight hug.

"Uncle Barry..?" Wally murmured, blinking to get the fog out of his eyes. Wally's voice with a deep baritone, making both the boy and his uncle start. Barry made an odd noise in the back of his throat and hugged Wally tighter.

"Uncle Barry, let go… What's going on?" Barry reluctantly let go, belated realizing that Wally had revealed his secret identity. Figuring that it didn't matter anymore, he pulled down his cowl in order to speak to his nephew face to face. "Are you alright?" He asked, "Do you hurt anywhere?"

"Sore…" Wally trailed off, moving his arm to lever himself into a sitting position. Unexpectedly, he overshot the movement and ended up only slipping his arm off of the bed. "What the-"

"Don't try to sit up." The doctor cut in. "Your brain still thinks you have the body of a ten year old. It will take a little while before you will be able to move properly."

This only served to confuse Wally further and he doubled his efforts to sit up. Barry shot Dr. Thompkins an annoyed look and gently held the boy down. There went his plan to introduce the idea to him gradually…

Dr. Thompkins backed off at the glare, letting the Flash handle the situation.

"Whoa there, Kiddo!" Barry caught Wally as his most recent efforts nearly ended up with him on the floor. He carefully helped the other into a sitting position, bodily moving Wally's limbs for him.

Wally clung to his uncle awkwardly, even his hands unused to their large size. Or their strength, Barry noted with a slight wince.

"Wally, what do you remember last?"

Wally's eyebrows furrowed in thought for a moment before his face dawned in understanding. "Oh! I was in your lab- the garage!" He cried excitedly, voice cracking mid-sentence. His hand flew over his mouth at the unfamiliar sound. "Uncle Barry…" He spoke hesitantly, unnerved by the familiar sound. "What's going on?"

"Wally… I think it's best if you see this for yourself." He passed Wally a mirror that the doctor handed him.

Wally only grew more nervous as he took the proffered mirror, only to drop it in shock a moment later.

"Aunt Iris is going to kill me…" Wally whispered in horror.

* * *

**In which the experiment that Wally replicates goes wrong and he is aged rapidly.**

**Sorry that it's short, this is a trial chapter of sorts. I've been playing around with this idea for awhile and finally decided to post it. I have a similar story that I'm working on as well. This is mostly a prologue in order to see how it is received.**

**This is going to be a Young Justice fic, so long as it continues. The first few to several chapters are going to be about how he adapts and becomes Kid Flash.**

**This is going to be a gen fic because, c'mon, he's mentally 10. I know that the Flashes do age faster mentally as well but I believe that much of it has to do with their mindset as well.**

**Anyways, hope you like it! Please comment your opinion on it!**


	2. Trouble in Paradise

Wally needed to be carried into the house.

His body couldn't seem to adapt to the sudden shift in size; his first attempt at standing ended up with Wally over-extending his legs and nailing Barry directly in the crotch. After she finished laughing at Barry's expense, Dr. Thompkins recommended that he exercise his muscles a bit before attempting again.

Although it had only been the better part of a day, Wally's molecules moving at an accelerated pace caused his muscles to atrophy severely from the 'years' of disuse. He would need to carefully get his body used to moving again before he could even think about walking - let alone being the Flash's sidekick.

Wally was frightened, he didn't understand why he couldn't move or why he was suddenly so much bigger. He drank in the doctor's explanations but listening didn't mean he understood. All of his fantasies entailed him beating up bad guys with his uncle, not all of this pain and confusion.

Barry did his best to help Wally, but it was a slow process. Genius or not, Wally still had the mental capacity of a ten year old. Lucky Barry, he got to experience the preteen and teen stage at the same time.

Iris was a whole other can of worms. When she finally accepted that, yes, that was actually Wally in her husband's arms she had banished Barry to the couch. It didn't affect Barry much, as his nights were spent in the garage, toying with chemicals. He worked deep into the night searching for a way to reverse Wally's failed experiment.

While Barry searched for a cure, Iris went through simple exercises with her nephew and helped him hobble around when needed. Wally for the most part remained silent, he felt guilty for the gap he'd wedged between his guardians and the sound of his new voice disturbed him.

Both Iris and Barry knew they'd need to return to work soon, their combined salaries was enough to keep them living comfortably but the addition of another speedster appetite would stretch their funds. Barry could hold off a bit on his heroing duties, at least. Jay was already aware of the situation and offered his help with patrolling until Barry could take it up again. He'd also called Elongated Man and asked him to expand his range until Barry could pick it up again.

Both of their bosses were breathing down their necks, Central wanted it's star reporter back and the crime department needed their best forensic analyst.

"You make more than I do, Iris. It only makes sense that you're the one who returns to work," Barry argued, voice pitched low so that Wally couldn't hear them.

Iris' eyes narrowed dangerously, her fingers rapping harshly against the arm of her chair. Barry winced, he was on a thin line if she was already tapping her fingers. "And how exactly do you plan to take care of Wally while you're working on a cure?" She asked, tone sharp.

"I can take a break from my research-"

Iris cut him off with a scathing retort, "Oh, so we're just going to let him lose five years of his life? Not even going to try and reverse this?"

"Then I'll go back to work and work on a cure from my lab there." He compromised, "The labs there are more than sufficient."

"And what about if someone sees you working on it?"

"I'll keep another case file next to me and switch it out if anyone comes in." He concluded proudly, assured of his plan's success.

Iris wasn't quite as impressed, "You're going to get fired for not doing any work, Captain Frye isn't stupid."

"I can speed through all the work, be done in a-"

"Flash, I know." She finished sarcastically. "Back to what started this problem."

"Iris-"

"Don't you start with me, Barry!" She snapped, voice raising. "You left the notes detailing exactly how you got amazing super powers within reach of an impulsive ten year old! What did you think he'd do, especially after Aquaman's just shown up with his own sidekick?"

"Well I didn't think he'd try to replicate it!" Barry yelled back defensively, "I didn't even think that experiment could be recreated, let alone by a child! How was I supposed to anticipate him building a lightning generator? That shouldn't have even worked as a substitute for real lightning! By all rights he should be dead-"

"Well you should have at least kept the notes in a more secure location! Dammit, Barry! I don't want another Zoom on our hands!" Iris seethed, "This isn't just about Wally, it's about the safety of our family!"

"So what, now I'm a danger to you?"

"Right now you're a danger to my sanity! Maybe if I'd never met you Wally wouldn't be hurt!" She exploded, eyes as fiery as her hair. She roughly jabbed a finger into his chest, pushing him back a step.

Barry puffed up with anger, matching her aggressive pose. "Yeah, and maybe he'd be in an orphanage or some terrible foster home! Without me, you wouldn't have been granted custody!"

"What's that supposed to mean?! It's not like you're ever home! Your influence has done nothing but cause Wally to try and kill himself!"

"He wasn't trying to kill himself-"

"Well that's not what it looks like! You said it yourself, the experiment should have killed him!"

"He was just trying-"

"Just trying to be like his Superhero Uncle who thoughtlessly throws himself into dangerous situations on a regular basis - What an amazing role model!" She yelled sarcastically.

"You said you were fine with my double life!"

"That was before it left Wally bedridden with five years of his life gone!"

"STOP!"

Barry and Iris snapped their heads up to behold Wally, tangled up in a blanket and clinging to the top of the banister for balance.

"Wally, how did you get out of bed?" Barry

"Who cares about how he got here, Barry!" Iris snapped, not taking her eyes off of the flimsy railing holding her nephew up. "I'm more worried about him falling!"

"He's been unable to move for days, forgive my curiosity." Barry drawled scathingly. "And I'm not exactly concerned when I have superspeed-"

"There you go again with the superspeed-!"

"Stop fighting!" Wally cut in, eyes glassy from unshed tears. "You're supposed to love each other!"

The tension in the room abated instantly, anger dissipating in lieu of concern over their nephew.

"Oh baby, we do," soothed Aunt Iris. "Your uncle and I are just having a... disagreement. It doesn't mean we love each other any less." Barry nodded in agreement, placing his arm over his wife's shoulder to convince Wally. Iris twitched in annoyance but otherwise didn't move away.

Their show didn't calm Wally, however. "That's what mom and dad said! Then they got a divorce and left me all alone! I don't wanna be alone again!" He stamped his foot childishly, accidentally bringing his leg up almost to his chest as he did so. In an attempt to correct, he quickly lowered his foot back down, once again misjudging the distance as well as the speed. It resulted in a very foot-shaped hole at the top of the staircase and, consequently, the roof of Iris's office.

Barry sped up the stairs to check Wally for injuries, Iris following behind at a normal speed. The redheaded woman engulfed her surrogate son in a tight hug, ignoring how he was taller than her and pressing his tear-streaked face into her chest.

"Oh baby, no. We love you and each other too much for that." She said, brushing her fingers through Wally's hair. At least his hair was the same, as red and soft as ever.

Barry joined in the hug, wrapping his arms around the two redheads and sheltering Wally between him and Iris. "We love you, kid." He agreed, resting his chin gently on Wally's head.

As the boy-turned-teen's sobs slowly quieted, Iris and Barry shared a look over the top of his head. If for nothing else, they would do this for Wally.

**-x-**

**Thank you all for reading and I'm sorry about the long wait for new chapters! If you find anything odd about the story feel free to message me and I'll do my best to fix it!**

**Please leave a review if you liked it! :)**


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